THE CATTLE DUNG PATCH

Soil samples were taken at 0–1 in. (0–2.54 cm) and 1–3 in. (2.54–7.62 cm) depths on five occasions over a period of 55 days from under (3 in. (7.62 cm) radius from centre) and around (9 in. (22.86 cm), 12 in. (30.48cm) and 18 in. (45.72 cm) radius from centre) dung patches deposited on pasture. The samples were analysed for available N, K and P. There was a significant increase in the level of all three elements in the 0–1 in. samples beneath the dung patch. The increase persisted throughout the experiment. K exhibited the greatest increase, but was not detected beyond the edge of the dung patch. The increase in soil N was smaller but was detected up to 6 in. (15.24 cm) from the edge of the dung patch. P also increased, but was more variable than either N or K. Soil N, P and K did not increase in the 1–3 in. samples. The weight and fibre content of the dung patch was also measured throughout the experiment. After high initial losses (25%) the dung patch decayed only slowly. The loss of ammonia from dung patches was followed over 13 days in a separate experiment During the relatively hot weather over this period approximately 5 % of the N iu the dung was lost as ammonia, mainly in the first five days. During the experimental period of 13 days 60% of the original weight of the dung patch was lost through evaporation. The results are discussed in relation to the growth of herbage surrounding a dung patch reported in the previous paper (12).     

THE DECOMPOSITION OF CATTLE DUNG AND ITS EFFECT ON PASTURE

A total of 228 separate dung pats voided by lactating dairy cows between May and October on a ryegrass/dover sward were studied for 2 years. The pats were on grazed swards receiving, on average, either 440 or 110 lb N/ac (492 or 123 kg/ha) per year. The mean area of the pats was 0.62 ft² (0.058 m²) with no difference in area between the pats on the two N treatments. On average, the pats on the high- and the low-N treatments crumbled in 63 and 55 days, respectively, and disappeared in 115 and 113 days, respectively. Pats deposited in July disappeared significantly quicker than pats deposited in May. The average area of rejected herbage around the pats was 2.63 and 084 ft² (0.244 and 0.078 m²), respectively, 1–2 months, and 1 year after they were voided; but after 2 years the affected areas were recolonized with ryegrass and clover and were grazed normally. It is concluded that the levels of N fertilizer applied had no differential effects on the breakdown of the dung and on the subsequent recolonization of the affected areas by pasture plants.     

THE LOCAL INFLUENCE OF CATTLE DUNG AND URINE UPON THE YIELD AND BOTANICAL COMPOSITION OF PERMANENT PASTURE

A study was made of the local effects on yield and botanical composition of the herbage of cattle dung and urine applied to permanent pasture as simulated defaecations and urinations.
A single application of urine had a negligible effect upon botanical composition. In the 2-ft.-diameter circle around dung patches there was an increase in cocksfoot, creeping bent, red fescue and white clover, and a decrease in herbs.
Urine patches were neglected by grazing stock for short periods only. Herbage around dung patches was neglected for a period varying from 13–18 months. The effect of this neglect was to restrict the spread of white clover around dung patches in comparison with similar plots kept short by cutting.
Yield response to urine in the area of deposition lasted for two cuts following application, response to dung for four cuts. An increase in crude-protein content of the herbage was recorded only in samples taken one month after application of dung or urine, and not later.
Increases in crude-protein yield following spring applications of dung or urine were greater than those following autumn applications. The inferiority of autumn applications may be attributed to winter leaching of nitrogen.     

A NOTE ON THE ZERO-GRAZING OF BEEF CATTLE

Groups of 8 steers weighing 300–400 kg (660–880 Ib) were rotationally grazed on a ryegrass-dominant pasture for 115 days. The systems compared were zero grazing (Z), field grazing conducted at the same stocking rate (FC), and field grazing conducted at a stocking rate varied with the intention of giving the same liveweight gain per uiimal as zero grazing (FV). Mean daily liveweight gains were: Z, 0.98; FC, 0.78; FV, 0.90 kg/animal (2.2, 1.7 and 20 Ib/animal), and liveweight gains/unit area were in the ratio 100:78:85. Organic-matter intake, measured on four occasions, was, on average, Z, 6.54; FC, 6.18; FV, 687 kg/head daily (14.4, 13.6 and 15.1Ib). From these results it appears that a comparison of zero grazing and field grazing made at the same stocking rate is likely to underestimate the potential of field grazing for beef production from grass.     

PASTURE DEVELOPMENT IN THE BEEF CATTLE REGIONS OF ARGENTINA

An account is given of the climate, vegetation and native pastures of the beef-cattle regions of Argentina. Though some of these native pastures have a satisfactory carrying capacity, most of them are defective in quality or low in productivity; there is considerable scope for increasing production through the establishment of sown pastures. Trials have been made with a wide range of grasses and legumes, principally of African and European origin. Though the pattern of species to be used in these regions is imperfectly resolved, the authors present a map showing tentative boundaries for temperate, sub-tropical and tropical species. Work to date suggests that pasture development can probably proceed over great areas without the use of fertilizers, and this adds to the attractiveness of pasture programmes. A problem of no less importance than the technical aspects of pasture improvement is that of gaining a greater investment of capital into the development of cattle estancias.     

THE CONTROL OF STOMACH-WORM INFECTION IN YOUNG CATTLE*

Study of the epidemiology of parasitic gastro-enteritis in calves suggested that control measures should consist of moving calves in mid-July to pastures not grazed by cattle since the winter and at the same time giving them adequate anthelmintic treatment in order that they should not contaminate the new pasture. Controlled trials are described in which calves managed according to these proposals made far better weight gains than comparable calves remaining on the same pasture throughout the season. Observations made in different parts of the country suggest that the same measures may be widely applicable. Possible causes of failure are discussed.     

THE USE OF CATTLE WITH OESOPHAGEAL FISTULAE IN GRASSLAND EXPERIMENTS

Oesophageal-fistulated calves and cattle were used in various experiments during 1963 to 1966; results for 1966 are reported.
The method of inserting the fistula, the routine care of the animals and the methods of sampling through the fistula, are described.
Individual stall-feeding experiments in 1966 gave recovery values of 99.7% for herbage extruded through the fistulae, in relation to herbage eaten. The in vitro organic-matter digestibility of the grass offered and of the extrusa samples were identical. The digestibility of the grass fed in these experiments was high, but was comparable with that of herbage used in the grazing experiments reported. Grazing studies on grass/white clover pastures are reported. The digestibility was determined on all samples and they were separated into various plant fractions. Results obtained were compared with herbage samples cut at the same time. In most cases the digestibility and % N of the extrusa sample was higher than that of the corresponding herbage sample. The quantity of dead material present increased, and more was eaten, as the season advanced; it was of low digestibility. Results of intake studies with grazing animals are presented and the use of oesophagea-istulated cattle as an aid in such studies is discussed.     

SOME OBSERVATIONS ON THE BEHAVIOUR AND HILL-PASTURE UTILIZATION OF IRISH CATTLE

During June to September 1966 grazing activities of four randomly selected individuals in a herd of 17 non-lactating, free-ranging cattle were observed on an Irish hill-farm of approximately 15 hectares which provided a choice of four distinct vegetative associations. A marked preference for Holcus-Poa-Anthoxanthum-Agrostis sward was noted. Grazing did not take place at night. During daylight it occupied three distinct periods, ceasing shortly after sunset and beginning at dawn.     

THE INFLUENCE OF NIGHT GRAZING ON THE GROWTH RATES OF ZEBU CATTLE IN EAST AFRICA

Results are reported from a 10-month trial, using 50 oxen, in which growth rates of groups receiving restricted and normal night grazing were compared. The resiriction of night grazing was found to lead to a significant decline of 30% in live-weight gain. This difference was largely attributed to periods of moderate grass shortage (i.e. marginal day grazing) when those animals with the longer grazing period were able to select a diet of superior quality and quantity. Under good, or very bad, grazing conditions the availability of night grazing did not appear to be critical.     

THE USE OF BARN-DRIED HAY AND SILAGE IN FATTENING YOUNG BEEF CATTLE

A series of trials was carried out in which barn-dried hay and silage were fed to young fattening cattle with or without supplementary barley. Liveweight-gains on silage and barn-dried hay alone were too low to provide an adequate finish during winter feeding. Liveweight-gains on hay alone were always higher than those obtained on silage alone, the difference being more marked in lighter animals. There was a marked response to supplements of 3 and 4 lb (1.4 and 1.8 kg) of barley, the response being significantly greater in silage-fed cattle than in those fed on barn-dried hay. There was some evidence of growth compensation with the introduction of a barley supplement to cattle on silage diets, but there was no such response in those fed on hay. Compensatory growth was not accompanied by improved digestibility or N retention.     

THE EFFECT OF DUNG AND URINE AND ITS INTERACTIONS WITH APPLIED NITROGEN, PHOSPHORUS AND POTASSIUM ON THE CHEMICAL COMPOSITION OF PASTURE

The importance of the grass/clover balance of a pasture in determining the effects of manurial returns and fertiliser applications on the chemical composition of the sward is shown.
The response to applied nitrogen was very dependent on the presence or absence of the animal excrements. For example, the N recovery from an application of 18 cwt. per acre of nitro-chalk was only 2% in the absence but 68% in the presence of the grazing animal.
Urine caused a marked increase in the N and K content and the yield of pasture, particularly when returned in quantity to a high-producing grass-dominant sward, and at the same time tended to depress the Ca, P and Mg content. Urine K was superior to fertiliser K, per pound of K returned or applied, in raising the K content of the pasture.
By comparison, dung had little direct effect on chemical content; even when returned in large amounts it affected the Ca and K content of the pasture to a relatively small extent. The P returned in the dung had little effect on the P content of the pasture and was inferior to superphosphate in this respect.
Together, as in normal grazing, dung and urine tended to counter or enhance their individual effects.
There was a positive correlation between the Mg and P content of the pasture and a negative correlation between Mg and K. Brief mention is made of the possible importance of the nutrient balance in pasture as a factor in animal health.     

THE EFFECT OF LENGTH OF SILAGE ON ITS VOLUNTARY INTAKE BY CATTLE

Trials are described in which the intake of silage of varying length was determined. The results indicate that a higher voluntary dry-matter intake occurred as the length of the silage became progressively shorter, but this effect appeared to diminish when the silages were supplemented with concentrates. Data from one trial indicate that reducing the length of hay had no effect on voluntary intake when concentrates were fed.     

THE INFLUENCE OF THE QUANTITY OF HERBAGE OFFERED AND ITS DIGESTIBILITY ON THE AMOUNT EATEN BY GRAZING CATTLE

Six calves, six heifers and six dry cows grazed a mature sward (treatments A and B) and a leafy aftermath (treatment C) in succession. The yields of herbage on the two swards were 7100 lb and 1950 lb DM per acre (7950 kg and 2180 kg per ha), respectively. The amounts of herbage offered daily were 47 lb (21–5 kg) DM per head (treatment A), 70 lb (32 kg) (treatment B), and 60 lb (27 kg) (treatment C), Two estimates of herbage organic–matter intake (O,M,I,) were made on each treatment; records of grazing behaviour were made on treatments B and C, The digestibility of the diet selected on treatment C was higher than that selected on treatments A and B, and the animals ate significantly more O,M, on treatment C, The total grazing times on treatments B and C were similar, but the animals found it more difficult to graze on treatment B
Herbage O.M.I. increased significantly from treatment A to treatment B, even though the quantity of herbage offered per day on treatment A greatly exceeded the amount eaten. The increase in O,M,I, was found to be associated with an increase in faecal 0,M, output, but the digestibility of the diet did not change.     

THE EFFECT OF NITROGEN AND STOCKING RATE ON THE OUTPUT OF PASTURE GRAZED BY BEEF CATTLE

An experiment was conducted in two successire years to measure the effect of two levels of fertilizer N, 50 and 300 kg/ha (45 and 270 Ib/ac) on the productivity of pastures grazed by young beef cattle. Two stocking rates were imposed at the lower N level and 4 at the higher level. The responses per kg fertilizer N were approximately 1 kg liveweight gain, 20–24 Meal ME and 8–9 kg DM. Maximal yields of about 1000 kg gain/ha (890 Ib/ac) and 19,000 Meal ME/ha (7700 Mcal ME/acre) were recorded. Animal performance was similar on the low and the high N pastures. There was evidence that the chemical quality of pasture was lower on the low N pasture in the first year, but there was no difference in the second year. The numbers of dung pats per ha and the refusal of herbage due to fouling were reduced by Increasing the stocking rate.     

SOILAGE FOR BEEF CATTLE

Over three seasons, 1957–9, soilage or zero-grazing was found to be more efficient than rotational grazing. This increased efficiency amounted to a 5% greater output of beef per acre and 8% greater stock-carrying capacity.     

GRAZING MANAGEMENT FOR DAIRY CATTLE

Many studies in recent years have stressed that grassland provides the greater part of the feed requirements of ruminant livestock in temperate lands, that a large proportion of this is supplied as grazing (83, 122) and that in this form it is the cheapest source of feed for ruminants (25, 38, 40). Several authors have contrasted the production estimated to be available from pasture with the much lower proportion—about 50% (74, 116)—harvested by the animal. For these reasons the efficiency of grass utilization under grazing conditions has received intensive study in the past 20 years and many of the principles of grazing management have been elucidated. Consideration of grazing management involves a study of the needs of the animals to be catered for, the sequence of grass crops which may be grown over the season, including the influence of special-purpose pastures and of fertilizer treatment on the yield and seasonal distribution of production, and the effective conservation of surplus herbage. In this review, however, attention is concentrated on the problems concerned in grazing management for the dairy cow during the main growing period of the year. The object of grazing management may be defined as 'to ensure a large supply of nutritious grazing over the growing season at a low cost and to utilize it in such a manner that physical waste of herbage and inefficient utilization by the animal are minimized and the productive capacity of the sward is maintained'. It is a complex subject, involving many interrelated factors including botanical, animal and per-acre considerations. These are briefly outlined before the available experimental data in grazing management practices are considered.     

THE EFFECT OF NITROGEN, STOCKING RATE AND GRAZING METHOD ON THE OUTPUT OF PASTURE GRAZED BY BEEF CATTLE

An experiment was conducted in 1971 and 1972 to study the effects of two levels of fertilizer N (50 and 504 kg/ha) on the productivity of pastures grazed by young beef cattle. Two stocking rates were imposed at the lower N level and three at the higher. In addition to rotational grazing, set-stocking and an integrated grazing-conservation system were included. The responses/kg N were approximately 1 kg live-weight gain, 19–24 Meal ME and 8–9 kg DM. Maximum yields of 1200–1300 kg live-weight gain/ha and 25,000–27,000 Meal ME/ha were recorded. Productivity of set-stocked pasture was similar to rotational grazing at the high N level, but lower at low N. The integrated system yielded comparable results to high-N rotational grazing. Performances and herbage intakes per animal reflected the stocking rates imposed.